1. Field of the Invention
The present invention relates to the determination of an optical property of a device under test (DUT) by analyzing a response signal of said DUT, or a signal derived therefrom.
2. Brief Description of Related Developments
According to a known technique commonly referred to as “swept homodyne interferometry”, a DUT is implemented in one of the interferometer arms of an interferometric measurement set-up introducing an additional wavelength dependent optical path length. A laser source is swept over a range of wavelengths. Due to a discrepancy of the arm lengths a modulated signal—the interferogram—is observed at a detector. The set-up is comparable to a Mach-Zehnder set-up when viewed in transmission, and to a Twyman-Green interferometer when viewed in reflection. More details concerning this approach can be found in “Phase and Group Delay Relation in Swept Homodyne Interferometry” by Thomas Jensen, and in EP-A-1202038 by the assignee, the teaching thereof shall be incorporated herein by reference.